This Small Business Innovation Research Phase I project seeks to demonstrate the initial "proof-of-concept" of utilizing silica gel encapsulated (SGE) cell therapy for the sustained delivery of low dose Interleukin-2 immunotherapy for the ultimate treatment of HIV/AIDS patients. Immunoprotected genetically altered human cells that express IL-2 would manufacture and secrete IL-2 continuously within the patient for several months or longer per single subcutaneous injection. Low dose IL-2 immunotherapy has been recently demonstrated to rapidly restore immune function in HIV/AIDS patients. In this phase 1 program, we propose to demonstrate the silica gel encapsulation of two types of human tissue cells in which IL-2 cDNA and an inducible promoter gene have been engineered into the cell line. Both immunological changes (i.e. WBC, NK, CD4+, and CD8+ levels) and plasma IL-2 levels will be followed in mice as a function of promoter administration and dosage. In this brief Phase I study, we seek to demonstrate the preliminary feasibility of sustained delivery of IL-2 immunotherapy using immunoprotected IL-2 secreting human tissue cells both in vitroand in vivo. If successful, this will set the stage for further development in the anticipated Phase II program. PROPOSED COMMERCIAL APPLICATION: Low dose IL-2 immunotherapy addresses a $4 billion AIDS market that is unfortunately continuing to grow at a rapid pace. Encapsulated cell therapy for IL-2 delivery addresses the need for better dosing control as well as patient compliance issues.